EP 1736247 A2 20061227 - Sound-electricity conversion device, array-type ultrasonic transducer, and ultrasonic diagnostic apparatus
Title (en)
Sound-electricity conversion device, array-type ultrasonic transducer, and ultrasonic diagnostic apparatus
Title (de)
Elektroacoustischer Wandler, Ultraschall-Gruppenstrahler, und Ultraschalldiagnoseapparatur
Title (fr)
Transducteur électroacoustique, transducteur ultrasonique de type réseau, et appareil de diagnostique à ultrasons
Publication
Application
Priority
JP 2005179959 A 20050620
Abstract (en)
The present invention aims to stabilize sound-electricity conversion characteristics of a diaphragm-type sound-electricity conversion device as well as to decrease the noise level of an ultrasonic diagnostic apparatus using the sound-electricity conversion device. The sound-electricity conversion device is configured by a capacitor cell including a lower electrode formed on a silicon substrate and an upper electrode over the lower electrode, the lower and upper electrodes sandwiching a cavity. An electrode short-circuit prevention film is formed on the upper electrode on the cavity side. The electrode short-circuit prevention film is formed of a material with an electrical time constant shorter than 1 second and longer than 10 microseconds, such as silicon nitride containing a stoichiometrically excessive amount of silicon. As a result, the electrode short-circuit prevention film has small electric conductivity, and thus it is made possible to prevent the film from being charged with electric charge and to avoid the drift of the electric charge. Consequently, the sound-electricity conversion characteristics of the sound-electricity conversion device stabilize, and further the sound noise level of the ultrasonic diagnostic apparatus decreases.
IPC 8 full level
B06B 1/02 (2006.01); A61B 8/00 (2006.01); H04R 19/00 (2006.01)
CPC (source: EP US)
B06B 1/0292 (2013.01 - EP US)
Citation (applicant)
- WO 0070630 A2 20001123 - CALIFORNIA INST OF TECHN [US], et al
- US 2003137021 A1 20030724 - WONG MAN [HK], et al
- "Analysis of LPCVD process conditions for the deposition of low stress silicon nitride. Part I: preliminary LPCVD experiments", MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, vol. 5, 2002, pages 51 - 60
Designated contracting state (EPC)
DE FR GB IT
Designated extension state (EPC)
AL BA HR MK YU
DOCDB simple family (publication)
EP 1736247 A2 20061227; EP 1736247 A3 20120822; EP 1736247 B1 20140514; CN 1886006 A 20061227; CN 1886006 B 20120328; JP 2006352808 A 20061228; JP 4523879 B2 20100811; US 2006284519 A1 20061221; US 7817811 B2 20101019
DOCDB simple family (application)
EP 06001863 A 20060130; CN 200610002116 A 20060116; JP 2005179959 A 20050620; US 34165506 A 20060130